Protective Effect Of N-Acetyl-Cysteine On Cadmium-Induced Injury Of Tubular Epithelial Cells Of Duck

The purpose of this study was to investigate the effect of cadmium on oxidative damage and apoptosis-related genes in tubular epithelial cells of duck and the protective effect of N-acetylcysteine（NAC）on it.10 to 15 days old ducklings were selected for the extraction and culture of renal tubular epithelial cells.The experiments were divided into control group（Control group）,low-dose cadmium group（LCd group,add 1.25μmol/L cadmium in cell culture medium）,middle-dose cadmium group（MCd group,add 2.5μmol/L cadmium in cell culture medium）,high-dose cadmium group（HCd group,add 5μmol/L cadmium in cell culture medium）,NAC control group（NAC group,add 100μmol/L NAC in cell culture medium）and NAC protection group（Cd+NAC group,2.5μmol/L cadmium and 100μmol/L NAC were added to the cell culture medium）,exposed cadmium sulfate（3CdSO4·8H2O）to the logarithmic phase of cell growth 78 h.After 12 h,the following indicators were determined:（1）Survival rate and morphology observation of duck renal tubular epithelial cells;（2）Detected the release rate of LDH inside of tubular epithelial cells,intracellular SOD,T-AOC,CAT activity and GSH,MDA content;（3）Activity of plasma membrane ATPase(Ca²⁺-ATPase,Na⁺/K⁺-ATPase)in duck renal tubular epithelial cells;（4）The mRNA expression of related apoptosis genes such as Bcl-2,Bak-1 and Caspase-3.The results showed:1.Compared with the control group,the survival rate of the cells in all cadmium groups was significantly decreased（P<0.05 or P<0.01）,Shrinkage,fragmentation and shedding of cell nuclei,and the degree of cell damage and survival rate were positively correlated with the dose of toxicants;2.The LDH release rate in each group was significantly higher than that in control group（P<0.01）;the intracellular SOD,T-AOC,CAT activity and GSH content were extremely decreased（P<0.01）,and the MDA content was extremely significant increased（P<0.01）.3.The Ca²⁺-ATPase and Na⁺/K⁺-ATPase activity of cell membrane in each cadmium group was significantly lower than that in control group（P<0.01）,the mRNA expression of Bcl-2 was significantly decreased（P<0.01）,and the mRNA expression of Bak-1 and Caspase-3 was significantly increased（P<0.01）.4.Compared with MCd group,the release of LDH in the NAC protective group was significantly decreased（P<0.01）,and the activities of cell membrane Ca²⁺-ATPase and Na⁺/K⁺-ATPase,SOD,T-AOC,CAT and GSH were significantly increased（P<0.05 or P<0.01）,MDA content decreased significantly（P<0.05）,while Bcl-2 mRNA expression increased significantly（P<0.05）,and the mRNA expression of Bak-1 and Caspase-3 was significantly decreased（P<0.05）.Conclusion:Cadmium could decrease the antioxidant function in tubular epithelial cells of duck,led to oxidative damage,which in turn induced changes the mRNA expression level of related apoptotic genes.Meanwhile,the effect of cadmium on the damage in renal tubular epithelial cells of duck presented a dose-effect relationship.NAC has obvious protective effect on oxidative damage of cadmium.